Zhan, It looks to me that 0002-gcore-ARM-ARM64-reserved-8-16-byte-in-the-top-of-sta.patch is independent of the ZRAM support. Without the patch, how does gcore behave? Fai or succeed? If gcore fails, could you show me a log indicating how gcore command fails? > -----Original Message----- > From: crash-utility-bounces@xxxxxxxxxx <crash-utility-bounces@xxxxxxxxxx> On Behalf Of ?乾利 > Sent: Tuesday, March 31, 2020 9:49 AM > To: crash-utility@xxxxxxxxxx <crash-utility@xxxxxxxxxx> <crash-utility@xxxxxxxxxx> > Subject: zram decompress support for gcore/crash-utility > > Hello list, > > > > When i try to use gcore to parse coredump from fulldump,I got below issue that make the coredump unavailable. > > 1. Zram is very common feature,in current android system supports zram swap,but gcore/crash-utility does not > support,even zram swap can decoded from ram,many page fault due to this reason. > > I added zram decompress feature to gcore,and i’m also considering wheather support zram in crash-utility,but for this > feature,i have to add miniLZO to codebase, I'm not sure if it's acceptable,plase help give some advice. > > miniLZO :miniLZO is a very lightweight subset of the LZO library,Distributed under the terms of the GNU General Public > License <http://www.oberhumer.com/opensource/gpl.html> (GPL v2+). > > http://www.oberhumer.com/opensource/lzo/ <http://www.oberhumer.com/opensource/lzo/> > > > > This change is a bit big,I attached it to the mail,if attachment is not available,you can also see these patch in github: > https://github.com/zhaoqianli0202/crash-gcore/commits/upstream > <https://github.com/zhaoqianli0202/crash-gcore/commits/upstream> > > Please review. > > > > 2. For historical reasons,kernel reserved top 8/16 bytes of stacks,but after kernel-4.14, this reservation was > cancelled,so gcore needs to improve compatibility. > > kernel change as below: > > commit 34be98f4944f99076f049a6806fc5f5207a755d3 > > Author: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx <mailto:ard.biesheuvel@xxxxxxxxxx> > > > Date: Thu Jul 20 17:15:45 2017 +0100 > > > > arm64: kernel: remove {THREAD,IRQ_STACK}_START_SP > > > > For historical reasons, we leave the top 16 bytes of our task and IRQ > > stacks unused, a practice used to ensure that the SP can always be > > masked to find the base of the current stack (historically, where > > thread_info could be found).™ > > ==== > > Patch for this issue: > > commit d1031df4617351a58b8edfb0121c306baaa34f9d > > Author: zhaoqianli <zhaoqianli@xxxxxxxxxx> > > Date: Mon Mar 30 12:07:02 2020 +0800 > > > > gcore: ARM/ARM64 reserved 8/16 byte in the top of stacks before 4.14, > > but this reservation was removed after 4.14 > > Without this patch,gcore counld't parse full callstack in version after 4.14 > > > > diff --git a/gcore.c b/gcore.c > > index f75701d..f6e1787 100644 > > --- a/gcore.c > > +++ b/gcore.c > > @@ -558,4 +558,16 @@ static void gcore_machdep_init(void) > > > > if (!gcore_arch_vsyscall_has_vm_alwaysdump_flag()) > > gcore_machdep->vm_alwaysdump = 0x00000000; > > + > > +#if defined(ARM) || defined(ARM64) > > +#ifdef ARM > > +#define STACK_RESERVE_SIZE 8 > > +#else > > +#define STACK_RESERVE_SIZE 16 > > +#endif > > + if (THIS_KERNEL_VERSION >= LINUX(4,14,0)) > > + gcore_machdep->stack_reserve = 0; > > + else > > + gcore_machdep->stack_reserve = STACK_RESERVE_SIZE; > > +#endif > > } > > diff --git a/libgcore/gcore_arm.c b/libgcore/gcore_arm.c > > index 891d01e..c8aefdf 100644 > > --- a/libgcore/gcore_arm.c > > +++ b/libgcore/gcore_arm.c > > @@ -29,7 +29,7 @@ static int gpr_get(struct task_context *target, > > > > BZERO(regs, sizeof(*regs)); > > > > - readmem(machdep->get_stacktop(target->task) - 8 - SIZE(pt_regs), KVADDR, > > + readmem(machdep->get_stacktop(target->task) - gcore_machdep->stack_reserve - SIZE(pt_regs), KVADDR, > > regs, SIZE(pt_regs), "genregs_get: pt_regs", > > gcore_verbose_error_handle()); > > > > diff --git a/libgcore/gcore_arm64.c b/libgcore/gcore_arm64.c > > index 3257389..ed3fdc8 100644 > > --- a/libgcore/gcore_arm64.c > > +++ b/libgcore/gcore_arm64.c > > @@ -28,7 +28,7 @@ static int gpr_get(struct task_context *target, > > > > BZERO(regs, sizeof(*regs)); > > > > - readmem(machdep->get_stacktop(target->task) - 16 - SIZE(pt_regs), KVADDR, > > + readmem(machdep->get_stacktop(target->task) - gcore_machdep->stack_reserve - SIZE(pt_regs), KVADDR, > > regs, sizeof(struct user_pt_regs), "gpr_get: user_pt_regs", > > gcore_verbose_error_handle()); > > > > @@ -124,7 +124,7 @@ static int compat_gpr_get(struct task_context *target, > > BZERO(&pt_regs, sizeof(pt_regs)); > > BZERO(regs, sizeof(*regs)); > > > > - readmem(machdep->get_stacktop(target->task) - 16 - SIZE(pt_regs), KVADDR, > > + readmem(machdep->get_stacktop(target->task) - gcore_machdep->stack_reserve - SIZE(pt_regs), KVADDR, > > &pt_regs, sizeof(struct pt_regs), "compat_gpr_get: pt_regs", > > gcore_verbose_error_handle()); > > > > diff --git a/libgcore/gcore_defs.h b/libgcore/gcore_defs.h > > index b0f5603..f31036c 100644 > > --- a/libgcore/gcore_defs.h > > +++ b/libgcore/gcore_defs.h > > @@ -1177,6 +1177,7 @@ extern struct gcore_size_table gcore_size_table; > > struct gcore_machdep_table > > { > > ulong vm_alwaysdump; > > + uint8_t stack_reserve; > > }; > > #/******本邮件及其附件含有小米公司的保密信息，仅限于发送给上面地址中列出的个人或群组。禁止任何其他人以任何形式 > 使用（包括但不限于全部或部分地泄露、复制、或散发）本邮件中的信息。如果您错收了本邮件，请您立即电话或邮件通知 > 发件人并删除本邮件！ This e-mail and its attachments contain confidential information from XIAOMI, which is intended > only for the person or entity whose address is listed above. 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